everyone is concerned about filtering the fuel that goes into a tank but no one ever wonders about the contamination that enters a tank through the pressure fitting from the engine. If the fuel gets contaminated with junk in the tank, then when you empty the fuel back into the fuel can you load the top of a filter with crap that gets flushed back into the tank on the next refueling. I think it is much better to have a fuel filter from the tank to the engine for insurance that an engine gets clean fuel.